You sound exactaly like me, This is my first but I am 29 not 17. But I have been having BHC since I was 30 weeks, and am now 35 1/2 weeks, they have been getting stronger sometimes for me too, and I get the pinch in my cervix, the doctor said it is probaby just the head pushing on a nerve, I get it off and on when I walk, and sometimes when I get BH. It *****! Sometimes it makes me gasp it hurts so bad! Sometimes it feels like a lot of pressure, and I think that is dialating, but I wouldn't worry too much you can dialate for a long time before you give birth. I was 1/2 cm dialated at 33 weeks. I've also been getting a little more of the watery discharge, unless there is a lot of it, I wouldn't worry too much. If there is a lot it could be amnotic fluid and you should call your doctor.
thank you keep me updated on everything with your pregnancy